Plunger construction



Dec. 1, 1953 D. G. KNOX 2,661,024

PLUNGER CONSTRUCTION Filed Aug. 8, 1947 Patented Dec. 1, 1953 PLUNGER. CONSTRUCTION Donald G. Knox, Los Angeles, Calif., assignor to The National Supply Company, Pittsburgh, Pa., a corporation of Pennsylvania Application August 8, 1947, Serial No. 767,401

6 Claims. (Cl. 137-692) This invention relates to plunger lift apparatus of the type used in lifting Well fluid by means of a pneumatically driven plunger whichtravels substantially the full length of an eduction tube. Apparatus of this general type is disclosed in the Fletcher patent, 1,846,000, dated February 16,

, 1932. Certain improvements in control apparatus for such devices are shown in the co-pending application of Knox et al., Serial No. 626,052, led November 1, 1945, now Patent No. 2,508,174 issued May 16, 1950.

One of the problems which is encountered in operatingplunger lift apparatus is that the valve which travels with the plunger sometimes does not remain in its open position for the entire length of the descent of the plunger Within the eduction tube. Premature closing of the valve results in short-stroking and consequentl loss of production. Various proposals have been made to provide means for holding the valve in fully open position against accidental closure so that the valve will remain fully open while the plunger drops from the surface to the bottom of the well. A coil spring for accomplishing this purpose is shown in the Rieker. patent, 1,905,058. One'difliculty with the Rieker construction is that the characteristics of a spring are such that a comparatively large force is kpresent tending to open the valve when it is in it-s closed position. 'I'his is an undesirable feature since it is important that the valve remain fully closed during the upward travel of the plunger Within the eduction tube.

Another problem which has been recognized in the operation of pluger lift .apparatus is that wax l or paraffin or lime, or other foreign matter, sometimes is deposited in the inner Wall of the eduction tube and the accumulation of such material may interfere with the normal action of the plunger. Various forms of scraper devices have been proposed, one of which is shown in the Bettis patent, 1,993,258.

It is the primary object of this invention to provide improvements in the construction of the traveling plunger as utilized in plunger lift apparatus.

A more particular object is to provide an improved device for automatically maintaining the plunger valve in its fully open position during descent of the plunger, yet which exerts la minimum force tending to move the valve from closed position.

A more particular object is to provide an an-V `nular permanent magnet through which the valve stem operates, which magnet is effective to hold the valve in fully open position.

Another object is to provide anovel form of mounting for such permanent magnet. p

Another object is t0 provide a scraper assembly for the plunger which will operate effectively irrespective of minor variations in the dimensions of the bore of the eduction tube which will pass across joints in the eduction tube 'Without diiiiculty.

Another object is to provide a scraper assembly having angularly positioned straight scraper blades curved on their outer edges to t the interior surface of the eduction tube.

Another object is to provide scraper blades of this type which are movable in slots under the action of a. band type spring.

' Another object is to provide a scraper device of this type in which the band type spring exerts unequal force' on a plurality of scraper blades, so that in traveling within the'eduction tube rotary motion is imparted to the scraper assembly.

A further object is to provide a scraper assembly of this type having a full opening through the interior thereof corresponding'with the opening within the tubular body of the plunger.

vAnother object is to provide one or more recesses along the scraper Vblade slots to receive foreign'material scraped from the inner surface of the eduction tube. Y l Y Other obj ects'and Iadvantages will appear hereinafter.

In the drawings: v

Figure 1 is an elevation partly in section illustrating a preferred embodiment of my invenion. y l f Figure 2 is a sectional elevation of the plunger shown in Figure 1, the plunger valve being in closedV position. y

Figure 3 is a transverse sectionalview taken substantially on the lines 3-3 as shown in Figure 1. I l

Figure 4 isa transverse sectional elevation taken substantially on the lines 4-4 as shown in Figure 1. Y Y

' Figure 5 is a partial sectional viewv on an enlarged scale showing details of the mounting of the permanent magnet.

Figure 6 is a sectional view on an enlarged scale partly broken away takenV substantially on the llines 6 6 as shown in Figure 1.

Referring to the drawings, the eduction tube l0 may comprise a plurality of.v jointed Vsections which depend into a ,Well bore. A plunger generally designated Il is adapted to travel the full length of the eduction tube froma position near the bottom of the well to the surface. The operation of such aplunger i`s IdserIibeI in detail in the Fletcherl and Ricker ,patents referred to above and "therefore need not be repeated here. In general the principal of operation is that gas under pressure below the plunger II raises the plunger together with a load of well fluid above the plunger within the eduction tube ID. The well uid is discharged through suitable conduits at the surface and the plunger II falls by gravity down toward the bottom of the well hole in order to bring up another load.

The plunger II comprises a tubular body generally designated I2. This body includesanl upper portion I3, a sleeveiIIl and a lowerportion I connected by the threaded elements I6. A" conical seat I1 is provided Yon the lower'portion I5 of the body member I2 and a poppet valve I3 provided with a head I9 is adapted to engage the seat/I1 to form a seal. An insert bushing" 20 is mounted within a counterb'ore2 I 'provided" in the lower endof' them'emberl`5 and secured" thereto ;by'any convenient means such asjforexample,

.by I brazing or' solderingf desired', the insert bushing maybe Ifrmed*integrally* withA the member I5 Thebiishing is provided with internal vthreads"'22"`for reception of'the external threads 23 provided on the support member v24, and shoulders25 on'the insert 2u and support 24 meet in 'abutting relation. Disassembly o1' the threads 22 and23may be preveiitedby any convenient means such'as; for example, by the pin '42. I A tapered .bore 25 isprovided in the upperportion of the support member '2.4 to receive the Acorresponding tapered sectionv 21 on the valve 4`ster n 28. MThe lower portion of' the valve stem 23 entendsithrough'the cylindrical bore 23 inthe lower end of the support 24. From this descrip- `tion it will be understood that closing movemerit of the valve is limited by the engagement of the valve head I5 with the seat I1' while the 4opening movement of'the valve'is llmited'by engagement of the` cooperating conical parts and 21. i h

A plurality of lateral portsv are provided in the lower `portion of the member I5 around the valve Vhead I9, and-these ports establish communication between the y space 3I within'- the eductiontube and below the plunger 'II and the central opening 32 Within the plunger II. AWhen the valve I8 is in its fully open position as shown .1in-Figure 5, gasor well huid or both may how up- I lwardlythrough the ports3 and into the central opening 32 and thus permit the plunger .I2 to fifdescend' within the eduction tube I0. If the valve l I8 should y' accidentally be jarred Vinto its 'closed position during such descent, gas 'pressure below the plunger might haltrthe descentl prematurefly Aand return the plunger tothe surface with Yonly a partial load. In order to prevent this action fromoccurring,- means are'provided for main- I-gtaining the valve l8 in its fully openoposition. As shown in the drawings this means includes .an annular permanent magnet `33 which has a cenf-ftral opening 34 through which the valve vstein 28 extends. The magnet33 isprovided with a -conical surface-35 at `its upper -end which is adapted to'engageunder a shoulder 3 6 at the upper end of .the bore'- 31 inthe insertbushing L20. A:Aresilient-z cushion or `rubber washer y38 is fvsfp'ositionedffati. the loweriend of i :the annular -magnet` 33,` andlthis washer'38 is'distortedjbe- Ltween themagnetv33and the upperendf 39!V on the support member- 24.

"since theematenai of-'whciif theemagnetifis constructed may be brittle, it is highly desirable nentmagnet upon ass'legrib ing 23.` Although the upp head I9, the partsy doJ. not; Contactd but, on the 'contrary a clearancejspace- 4I is provided.. Ini

Aered section'l 21 Qitlie valve o lle-tapered, bore.; 2,6, within the that thel valve head and magnet;

@tanto-.metal engagement, and. l n qthereby.- further protected against; shoclgolo'ading or fracture. Even if such= metal@ vtoinretalicontact should occur by reason of wear of the` parts 26 and 21 the cushion 38 would abn other words, the

vided on-'the plunger I Ito-"removesuch foreign *material fas' it` accumulates. As fsh'ownii-lin 'the drawings, thev sleevel l-connecting thebodyfportions `I3 `and 15" isprovided with` apluialityl of straight slots 45 extending longitudinally "and atA an angle to the axis ofthe'l'eduction tube lit., `Each of 'these' slots1f45=`may."be "formed with straightsides'byfmeans ofY a" milling cutter if' desired. 'Recesseslilvare- 'providedalong'the length of l"the *slots'21'45 fori a lpurpose described below.

'A"scraperibla"de 411 is "positioned withinieach or the slotsfili5 'and is's'lidably-'received-so that are adapted toflunderlieiahriiilarelips' 49 andiE f Iprovided "onthe'f members I 3 andv I 5 respectively.

f outward ia'dial'movenient l"of '-the blades 41 A band'type'spring 5I is'rece'ived'within al groove,

The *pressure exerted by' y the a minimum frictional force is developed between theblades f41 andthe ed'iiction tube-TI D; 'and hence fthe I'travel plunger 4I I within-the' du'cticn tube lIl'Iv isl 3 not- `l matrially affected. The band springy 5 I, whichflis split atff exerts unequal loading of the blades 41 results 'in rotationofthe iplunger "assembly as it"'r'ri'oves vertically within l the jeductior'i'tube.

it zwur-te-fobseifv'eci 'from reconsideration-"of Figures 4 and 6 that the scraper bladesand' the hamstring 5 I" are coned'wuiin "uae inici:- nesaf the tubular" obey member, and' "that" a full. opening is prvidd'thro'ugh 'the sleeve merri- `loer FI4. vThis is an impor-tant featuresince it't is necessary to avoid any restriction of the central fopening -32 -in order'fthat 'certain appliances may "be loweredfinto this'fopeningrshould" abnormal well'fc'onditions 'or otherfcauses result inV4 stickjoints of the eduction tube I.

scraperblade 4l may be relieved as shown in order to avoid interference or fouling in the Y t Y t The clearances providedrby these relieved portions '56 and the clearance between'the projections 48 and lips 49 are exaggerated in Figure 6 for clarity of illustration. Furthermore, these upper and lower portions of the scraping edge may be beveled as shownat 55 in Figure l to reduce the 'blunt end 'of the blades 46 substantially to a point. In

this way the accummulation of foreign matter at the blunt ends of the blades is avoided.

In operation the vertical movement of the plunger ii within the eduction tube le causes the scraper blades 4? to remove any accumulation of wax, parain or other foreign matter from the bore of the eduction tube and to deposit it within the recesses #l5 along the length of the slots d5. The foreign material thus removed from thev internal wall of the eduction tube may pass inwardly through the recesses 4S into the central opening 32 or may remain in the recesses 6 and be redissolved into the well iiuid when the plunger H returns to the lower end of its stroke.

It will be understood that the number oi blades employed or the angle of the blades with respect to the axis of the eduction tube may be varied in order to sweep a full circle of the eduction tube if desired as the plunger moves therein.

Having fully described my invention, it is to be understood that I am not limited to any of the details herein set forth except as described in the following claims.

I claim:

1. A swab plunger comprising a tubular body member having a longitudinal passageway extending therethrough, said body member being provided with lateral ports near the lower end thereof, valve means for controlling flow through said passageway and ports, said valve means including a valve seat on the body member above the ports, said means also including a valve having a head and a depending stem, guide means on the tubular body member below the ports slidably engaging the stem to guide the valve for longitudinal movement with respect to the body member, the valve head being adapted to close into contact with said seat, an annular permanent magnet fixed on the body member and encircling the stem at a location between the guide means and said ports, the magnet acting on the valve head to maintain the valve in open position, and cooperating stop means on the Valve and body member limiting opening movement of the valve and preventing contact between the valve head andthe magnet.

2. Aswab plunger comprising a tubular body having a longitudinal passageway extending therethrough, valve means near the lower-end of said body for controlling ow through said passageway, said valve means including a valve seat on the body, said means also including a valve having a head and a depending stem, a support secured on the tubular body slidably engaging the stem to guide the valve for longitudinal movement with respect to the body, the valve head being adapted to close into contact with said seat, an annular permanent magnet clamped between the body and the support and encircling the stem, the magnet acting on the valve head to maintain the valve in open position, and cooperating stop means on the valve and support limiting opening movement of the ,valve to prevent contact be-a tween the valve head and lthe magnet.

3. A swab plunger comprising a 'tubular body having a longitudinal passageway extending therethrough, Yvalve means near the lower end of vsaid body forcontrollingv ilow through'said passagewaysaid valve Ameans including a valve seat on the body, said means also including a valve having a head and a depending stem, a support secured on the tubular body having a'bore slidably engaging the stem to guide the Valve for longitudinal movement withrespect to the body, the valve head Ibeing adapted to close into contact with said seat, an annular permanent magnet encircling the stem, an annular resilient washer, the magnet and washer being clamped between the support and the body, the magnet acting on the valve head to maintain the valve in open position, and cooperating stop means on the valve and support limiting opening movement of the valve to prevent contact between the valve head and the magnet.

4. A swab plunger comprising a tubular body member having a passageway extending therethrough, a valve seat near the lower end of the body member, a valve having a head and a depending stem guided for movement on the body member, the valve head closing into contact with said seat to prevent iiow through the passageway, an annular magnet on the body member encircling the stem and acting on the valve head to maintain the valve in open'position, and cooperating stop means on the valve and body member limiting opening movement of the valve and preventing contact between the valve head and the magnet.

5. A swab plunger comprising a tubular body having a longitudinal passageway extending therethrough, valve means near the lower end of the body for controlling flow through said passageway, said valve means including a valve seat on the body member, said means also including a valve having a head and a depending stem, the body having a counterbore provided with an annular shoulder, a tubular support having a central opening receiving the valve stem, an annular magnet encircling the valve stem and positioned within the counterbore, the valve head closing against the seat, the magnet acting on the valve head to maintain the valve in open position, a resilient washer interposed between the annular magnet and the tubular support, and thread means connecting the tubular support and body for clamping the magnet between said annular shoulder and said resilient washer.

6. A swab plunger comprising a tubular body havmg a longitudinal passageway extending therethrough, valve means near the lower end of the body for controlling flow through said passageway, said valve means including a, valve seat on the body member, said means also including a valve having a head and a depending stem, the body having a counterbore provided with an annular shoulder, a tubular support having a central opening receiving the valve stem, an annular magnet encircling the valve stem and positioned within the counterbore, the valve head closing against the seat, the magnet acting on the valve head to maintain the valve in open position, a resilient washer interposed between the annular magnet and the tubular support, thread means connecting the tubular support and body for clamping the magnet between said annular shoulder and said resilient washer, and cooperating means on the valve stem and support for limiting 152,918,204 i; I. 2,216,809 l .2,346,904 2,353,719`A the anulmgnet, 'l "l 4'13011111115 d. KNOX.

fUNI'IVED STATES PATENTN` j; May 13, 1930 .A1613 `2,5I 1933 10 [Nog-.m7, 1933 Mar; 5, 1935 31,558,105? ,905,058 Y. 1.934,548Qfy 4 

